Electric vehicles are on the advance around the world, promising substantially lower carbon emissions. Car part suppliers are adapting to this development. This innovative motor controller was conceived for ten-metre-long electric passenger coaches. An important part for running a coach, the controller provides power for the coach’s auxiliary systems. Its design is outstanding in that it is inspired by insights gained in bionics. The eight faces of the unit are ideally suited to follow the demands of the heat emission function. This well-proportioned arrangement is inspired by and modelled on diamond cuts as it favours heat emission in each direction. The homogeneous structure resulting from this ensured an optimal arrangement of the fixing-hole positions in relation to the heat sink. This led to both the system’s high efficiency and low weight. In addition, all interfaces for operation are located on the same face. The whole structure thus entails a compact design idiom and allows both easy installation and maintenance. The highly expressive design of this motor controller lends this kind of device a new aesthetic – a functionality that is closely linked systemically to the form, and which fascinates with its compelling logic.